Computer automation of high current ion implanters

Complete computer automation of a high current ion implanter has been achieved. Special design considerations were necessary for automation including the development of a simplified ion source, a simplified beam transport control function, and a computer aided real-time feedback dosimetry control system. A special, versatile software architecture was also necessary to allow protected operation by unskilled operators, as well as diagnostic and maintenance modes accessible only to qualified personnel. Integral mounting of the DEC LSI-11 computer in the implanter frame provided additional challenges regarding EMI control and the electrical isolation required. The end result is a system in which all pertinent functions of the implanter are computer monitored and controlled continuously, allowing for automatic set-up, operation, on-line fault detection and diagnostics, with recovery software to correct many transient problems as they occur. This paper will discuss both general and specific solutions to the design problems encountered, and will review the system performance from a user point of view.